As has been known for a long time, and as can be seen in particular from document FR-A-2 357 080, interconnections are made between the electrical conductors serving various electrical appliances by means of modules, in particular such as junction blocks. For this purpose, the modules include connection terminals, e.g. of the wire-clamping screw type, received in boxes where they are selectively interconnected by conductive strips, and in which they are accessible to conductors from the outside. The boxes are generally flat and of small thickness, and they are made of insulating material. Insertion openings are provided facing the connection terminals through some of the walls of each box so as to allow electrical conductors to be inserted for connection to the terminals. Other openings are also provided for passing a terminal-driving tool, such as a screwdriver for a terminal having a screw to clamp a wire.
Such connection modules are generally intended for mounting side by side in alignment with other modules that are identical or comparable, on a support which is conventionally a standardized rail, with each module being positioned transversely relative to the rail and being fixed thereto in predetermined manner by a base that carries positioning and fixing members for this purpose. Modules in alignment on a common support are placed side by side via their respective side faces of large dimensions. The openings are thus usually made through the remaining faces which are of smaller size, and referred to herein as "edge" faces. The openings for the driving tool are preferably provided in a wall or wall portion of the box situated opposite its base and thus highly accessible when the modules are mounted on a support, while the conductor-insertion openings are made in the remaining wall portions situated between the large side faces, the base, and the wall or wall portions opposite said base.
It has also been known for a long time, as can be seen for example in document FR-A-2 483 692, to provide modules such as junction blocks with switches to make it possible, in controlled manner, to electrically interconnect or disconnect strips that are situated in alignment within the same module.
As already mentioned in that prior document, junction blocks were already in existence having switches of the knife-blade type or of the sliding plug type, and it is stated that such switches require their contact pieces to be positioned very accurately and that a safety device was necessary to make positioning thereof reliable. To remedy those drawbacks, the above-mentioned document proposes a device enabling operation to be performed easily and quickly, with effective clamping and reliable positioning; nevertheless, implementation of that device is not without difficulty.